NON-PERIODIC CHANGES. 



77 



much smaller than in tlio winter, but tbey depend now much less on the minimum tempera- 

 ture ; the correlation factor between reduced range and minimum temperature in the summer 

 being only half what it was in the winter. 



Cotnparison of Non-periodic Temperature Changes at Cape Evans, Cap)eAdare and Framheim. — 

 Unfortunately no maximum and minimum observations are available at Cape Adare and Fram- 

 heim. Hence it is impossible to compare the aperiodic changes of temperature at these 

 stations with Cape Evans by the method just used. 



The comparison may be made, however, by the second method mentioned above. The 

 change in temperature from day to day depends almost entirely on aperiodic changes. The 

 difference has therefoie been taken between the temperature at the same hour on consecutive 

 days. At Framheim temperature observations were taken at 8 a.m., 2 p.m. and 8 p.m., the 

 mean difference between the readings at each of these observations and the corresponding one 

 on the following day have been u,sed. This gives 90 determinations of the change in a month 

 of thirty days. The changes have been grouped according to whether the temperature rose 

 or fell during the interval and the mean for the former entered in table 35 in the column 

 headed + and the latter in the column headed -•. (The occasions when the changes were zero 

 have been divided equally between the positive and negative groups.) In the right hand half 

 of the table the number of times the changes were positive and negative have been entered. 

 In order to make the comparison complete the same procedure, using the same hours, have 

 been applied to the observations made at Cape Evans and Cape Adare, the results being 

 entered in the same table. 



Unfortunately no observations are available at Cape Adare for January or February or 

 at Framheim for February and March. 



Table 35. 



To facilitate discussion the mean values of the interdiurnal variability irrespective of sign 

 have been entered in table 36 together with the mean temperature. 



